Dispensing system for liquefied gases



July 25, 1950 T. H. DUFF DISPENSING SYSTEM FOR LIQUEFIED GASES Fi ldMarch 22, 1945' 2 Sheets-Sheet 1 w m w A INVENTOR July 25, 1950 T. H.DUFF DISPENSING SYSTEM FOR LIQUEFIED GASES Filed March 22, 1945 2Sheets-Sheet 2 I02 I 4s 56' /6 2 2 oi l3 2/ THDUFF INVENTOR.

Patented July 25, 1950 T. H. Dufi, Dallas, Tex. Application March 22,1945, Serial No. 584,162

9 Claims.

1 a This invention relates tonew and useful im provements in dispensingsystems for liquefied gases, and is particularly adapted for use withhydrocarbon gases of the types of butane, propane, and the like. 7

One object of the invention is to provide an improved systemforcontrolling the vaporization and flow of gas from a liquefied gasstorage system. I

An important object of the invention is toprovide novel means forcontrolling the flow of vaporized gas from a liquefied gas storage tankto the 3 service outlet of the system.

- A particular object of the invention is to provide, in a device of thecharacter described, means for utilizing liquid columns to performavalving function between the stored gas and a vaporizing and dispensingchamber.

A further object of the invention is to provide improved means forcontrolling the level of lique fied gas which is permitted to enter thevaporizing chamber in a device of the character described. r

Still another object of the invention is to provide, in a system of thetype described, means for charging and for maintaining, a charge ofliquid in that portion of the system providing liquid seal separationbetween the storage tankand the vaporizing and dispensing chamber.

A still further object of the invention is to provide means forwithdrawing liquefied gas from the principal storage space of such asystem, conducting such liquefied gas into a vaporizing section of thesystem and there vaporizing the gas and sending it to a service outletin substantially the same mixture in which the liquefied'gas is presentin the storage space, thereby providing a-supply of substantiallyuniformvaporized gas. A stillfurther object-of the invention is to providemeans for reoffering low volatile or rich gases to the vaporizing anddispensing chamber during periods of considerable temperaturediiferential between the vaporizing chamber and the service lines,whereby such richfgases are notforced into the service lines at astimewhen they would be likely to return to liquid form therein, and yetprovide for a reoffering of such gases until temperature onditions aremore suit able for their acceptance in the service line in a. gaseousstate. i I

Still anotherimportant object of .the invention is to provide aliquefied gas storage and dispensing system having means for controllingthe vaporization and flow of vaporized gas, which means is valveless andfreeof mechanical parts or mechanisms.

Another object of the invention-isto jprovide in such a system means forsubstantially pre-- eluding contact of the stored liquefied gas withparts of the system that may absorb'heat incidental to and as a resultof the application of 3 heat for vaporizing purposes.

havingthe customary inlet valve l2, at its upper,

A further important object of the invention'is to provide a controlsystem for aliquefied gas storage and dispensing system particularlyadapted to be assembled as a prefabricated com- .2 pact component of acomplete system and which may be readily transported to other places forattachment to suitable storage vessels.

Still other objects of the invention are to provide a system which iseconomical to manufacture, simple in structure and operation, wellsuited to operation above ground and ofiering a practical system for useof flame or other applied heat to cause vaporization, and, particularly,a system suitable for complete enclosure without fear of mechanicalfailure or high maintenance cost.

y Additional objects and advantages of the in vention will be apparentfrom a readingof the following description of devices constructed inaccordance with the invention, and reference to the accompanyingdrawings thereof, wherein:

Figure 1 is a view, partly in elevation and partly in section, of adevice constructed in accordance with theinvention, and showing the samein normal operating po sition.

Figure 2 is a view similar to Figure 1', but showing the operatingportion of the device in the positionit assumes when excessive.withdraw-. als of gas are being made, V

.Figure 3 is an end elevation, 's howing .the heating chamber,

Figure 4 is a view, partly in elevation and partly in section, of amodified form of the device,

Figure 5 is a horizontal cross-sectional view taken on the line 5 5 ofFigured.

In the drawings, the numeral. I 0 designates an elongate cylindricalstorage tankv which is ,par-, ticularly adapted tobeset up above 'groundfor receiving- ,and holding for vaporizationliquefied gases, such asbutane, propaneand the like, and mixtures and combinations thereof;- Thetank isadapted to be substantially filled withlique fied gas underpressure through-a filler pipe ll end; and an escape pipe l3, having anoutletvalve l4. at its upper end, permitsthe vaporized gas tolflow fromthe tank asit is filled, preferably into .the filling tank truck (notshown),.or other supply source. Afloat gageelement-IS extends downwardlythrough the escape pipe, in the usual manner, for indicating the liquidlevel in the tank.

The control system includes a vapor chamber l6 having communication withthe vapor space H of the storage tank I!) by means of a U-shaped gasconductor member or tube l8. One arm IQ of the gas conductor. membercommunicates with the vapor chamber l6, while the other arm 2% standsupright in alignment with the filler pipe ll, as clearly shown in Figure1, and communi cates with the vapor space H of the storage tank. Thepassageway through the arm 20 is preferably smaller than the passagewaythrough the arm H, for reasons which will be hereinafter explained.

An elongate conduit 2| extends along the lower portion of the tank andoutwardly through one end wall thereof, as clearly shown in Figure l,and is then directed upwardly along the exterior of the end of the tankto the upper surface, where it extends inwardly to the vapor chamber I6.Upon entering the vapor chamber the conduit 2| is directed upwardly to apoint near the upper end of the chamber and is then turned upon itselfand extends downwardly in an inverted U-lshape to a point near the lowerportion of the chamber l6. A portion of the conduit 2% at the end of thetank is subjected to heat and may be enlarged to fo m a vap ri in s tion22.

It will be seen, therefore, that liquefied gas will be conductedthrough. the conduit 2| to the xp ns on ap rizin se tion 22. in h at sapp ied at h nl d xpa s on s i n, it wi l dil b n at th liq efi d g isanverted to the vapor state at that point and is tenduc ed in o h a o Chmber 16 in ac se n s term From the apor ch mber :6, th case-v ous gas isconducted through a service line out-. l t 23 at the pp -end t the chugh the usual fittings attached thereto, such as ex-. cess flow valvesand cut-cit valves-2 4, and a pressure regulator 25, permitting flow ofthe gas through the service line to thepoint, of consumpont il a so beseen tha he cases in the vapor space I! of the storage tank havecommunication with the vapor chamber Hi by means of the. gas conductormember 18.

For controlling the flow of g s from the tank, columns of liquefied gasare introduced into the gas conductor member l8 and the liquid conduit2!. As the tankis filled, it. will readily be seen that liquefied gasentering the filler pipe ll will be directed into an enlarged bowl 26formed at member o. th same lev l hat t ris s in he stor tankelongatespilier spout. 21 will ca ry fluid m h bowl .6. o, an upr h nine. 8 comu i a ing a its o er nd wi h the co ii 21- Th r re q efied a e ing hebQ l .5 w n. l the a m 0 i. h U- an d qu e er mem er a w l flow u h espiller 21- into the upright pipe 28 filling it, and pa t y fill g the odu h as has lre y n. expl e i uefi d s i not low h u h either t sheredconduc r m be 1 r. the conduit 2| intothe'vapor chamber |'6, since thevalve 24 in the outlet pipe 23 is normally closed during the fillingoperation and the trapped air or gas in said conductor member andconduit prevents the liquefied gas from rising through said conductorand conduit to the vaporizing chamber. Also, the liquid gas will fillthe tank only tothe level of the lower end of the escape pipe l3, anyexcess liquefied gas flowing out through such escape pipe.

The inner end of the conduit 2| is preferably formed with a bafliechamber 29, having an opening 38 provided therein near the bottom of thestorage tank H). A bafile plate 3| having an opening 32 therein ispositioned within the chamber 29 between the opening 30 and the lowerend of the upright pipe 28. It will be seen, therefore, that the pipe 28will constantly be filled with liquefied gas to the same level as thatin the storage tank In, since its lower end communicates with theliquefied gas through the opening 30 and its upper end is open to theVapor space |'T".'

A flame or other source of heat 35 may be ap-f plied to the vaporizingsection 22 of the conduit 2|, as illustrated in Figure 1, to causevaporiza tion of the liquefied gas entering said conduit. A baffle plate31 may be positioned between the vaporizing section 22 and the endportion of the' tank, to prevent radiation of heat from the'section 22to the tank. Also fins (not shown) may be provided on theconduit 2| toreduce conduction of heat therealong. To further preclude heating of thestored liquefied gas, an elongate braille sleeve 40 surrounds the majorportion of the conduit 2| lying at the lower portion of the tank ill.Since liquefied gas can not enter this sleeve, the dead gas spacetherein will afford insulating qualities. A similar sleeve or cylinder4| surrounds the arm IQ of the U-shaped conductor member H! whichcommunicates with the vapor space "5. The sleeve is connected to thetank H! with a, gas-tight joint; and liquefiedgas will rise in theannular space between thearin l9 and the sleeve 4| only a portion of thelength of the arm l9.

A closure or housing 45 may be affixed to the tank I!) to enclose andprotect the filler pipe, vent pipe, vapor chamber, service outlets andvalves connected therewith;

In use, the tank In is filled or charged by introducing liquefied gasthrough the'valve i2 and filler pipe while permitting displaced vaporsin the tank to escape through the vent pipe l3 and check M, preferablyto be returned to the supplying tank truck (not shown). As has beenexplained, a portion of the liquefied gas will enter the U-shapedconductor member is and will overflow from the bowl 26 through thespiller' pipe 21 into the upright pipe 28 communicating with the conduit2| and vaporizing section 22; Since the liquefied gas can not risematerially in the arm I}! of the U-shaped conductor or in the conduit 2|because of the air or gas trapped in the conductor and the conduit whenthe valve 24 in the outlet pipe 23 is closed, theremainder of theliquefied gas will overflow into the body of the tank to charge it to apredetermined level, ordinarily limited or determined by the position ofthe lower end ofthe vent pipe l3. It is to be noted that the liquid bodyin the tank It] is 'preeluded from rising to the level of the upper endof the arm 20, whereby such arm always has communication with the vaporspace I! in the tank.

Also, when the tank is. completely filled, it will be noted that thebaffle chamber 29 iscompletely filled and that the liquefied gas standsin the .same diameter.

upright pipe 28 and'a" substantial height in the conduit 2 I. When heatis applied to the vaporizing section-22, the liquefied gas therein isvaporized and, if not withdrawn as generated, will force the level ofthe liquefied gas back along the conduit 2| toward themain' storage ofthe tank III through the opening 30.

The gases formed in the vaporizing section and conducted by means of theconduit 2| to the vapor chamber I6, will force the liquefied gas in thecOndllit 2| back against the higher liquid level of the liquefied gas inthe main storage tank Ill because the vapors in the chamber l6 areprevented from returning to the vapor space I! of the tank II] by meansof the liquid seal provided by the column of liquid standing in the U-shaped conductor member I8. The liquefied gas in the arm I9 will alsorecede because of the pressure of the gases overhead, thus raising thelevel of the liquid standing in the arm 20. Since the liquid may rise inthe arm 20 to a point above the highest liquid level in the tank I 6,the vapor in the chamber I6, communicating with both the arm I9 of theU-shaped gas conductor member and the liquid conduit 2I and applying thesame gaspressure against the liquefied columns therein, will force theliquefied gas in the conduit 2I back into the main storage tank I0,through the opening 30, before the liquefied gas in the conductor I8will be forced out of the upper end of the arm 20.

' In normal operations, as the vaporized gas is withdrawn from thechamber I6 through the service outlet, liquefied gas from the storagetank will enter the liquefied gas conduit 2! and fiow to the vaporizingsection 22, where the applied heat causes rapid vaporization insuificient quantities to meet normal consumption. During suchoperations, the vaporized gas in the vapor space I! of the storage tankis precluded from entering the service outlet by the column of liquid inthe U-shaped gas conductor I8.

- Under conditions of excessive withdrawal, beyond the capacity of theheating or vaporizing section 22, or in the event the application ofheat is discontinued, the supply of vaporized gas entering the chamberl6 through the liquefied gas conduit 2| may not be adequate. Theliquefied gas may then rise in the conduit 2| as shown in Figure 2. Dueto the relatively small surface exposed to heat of the surroundingmedium, the supply of vaporized gas from the conduit ZI will ordinarilynot be sufficient to meet normal consumption. In such case, vaporizedgas will .benwithdrawn from thevapor space I! of the storage, tank Ithroughthe'gas conductor I8. As the pressure in the chamber I6 isreduced by withdrawal of vaporized gas, the column of liquid within theU-shapedgas conductor I8 will rise in the arm [9 and fall in the arm tothe positionshown in Figure 2.v When 'theliquid in the arm 20 hasreached the lower end of the erect portion thereof,. the vaporized gasfrom the vapor space H maybubble across into the arm I9 and upwardlyinto the chamber I6, where it will enter the service outlet.

:::, Ithas already been'mentioned that the diameter of the arm I9 ispreferably larger than the diameter of the arm 20. This is desirable inorder that the height of the column in the arm I9 may neverahave-tocriseas high as it .would if the arm I9 were the same size as the arm 26,thus reducing the liquid pressure head therein. If desired, however, thetwo arms may be'ofthe The withdrawal of vaporizedgas from the vaporspace I! may continue during the period of abnormal withdrawal, or untilthe source ofheat applied to the vaporizing section 22 is renewed orrelighted. When the flame or heat has been reapplied to the vaporizingsection 22, or the period of excessive Withdrawal has passed, an amplesupply of gas will be delivered through the conduit 2I to the chamber I6to meet normal withdrawal through the outlet 23, and the columns willagain resume the positions illustrated in Figure 1. 1 The provision ofthe inverted U-shaped portion of the conduit 2| within the chamber I6 ismade in order to deliver the vaporized gas in the chamber I6 at a pointspaced from the outlet 23 to preclude delivery of heavy or. rich gas tothe outlet under conditions which would permit condensation of such gasin the, service line. Should such heavy or rich gas be delivered to thechamber I6, it may condense in the chamber and fall into the arm I9 ofthe U-shaped gas conductor I8, adding to the column of liquid therein.

As the column of liquid in the conductor I8 is increased, the liquidwill rise in the arm 20 and into the bowl 26 where it will fiow throughthe spiller pipe 21 into the upright member 28 and will be delivered tothe baffle chamber 29. Thus, the heavier or rich gases will again beoffered into the conduit 2| and vaporizing section 22, where they willbe revaporized and again de: livered to the chamber I6. In this manner,the heavy or rich gas is reoffered into the chamber I6 for delivery tothe service outlet 23 until conditions of temperatureare such that therich gases may fiow through. the service line without condensation.Also, the liquid column in the conductor is maintained by thiscondensation process.

A slightly modified form of the invention is illustrated in Figures 4and 5.

In this form, the U-shaped gas conductor is formed for concentrictubular members, one of which is a depending extension 50 of the vaporchamber I 6. A sleeve 5| closely surrounds the lower portion of thechamber and is closed at its lower end. The upper end of the sleeve isformed in an enlarged dish shape, as illustrated at 52. The dish has aspout 53 which is positioned to discharge liquids entering it, into theupright conductor 28, communicating with the liquefied gas conduit 2I.The cylindrical insulating member 54 is affixed to the under side of thedish 52 and extends downwardly around the sleeve 5|, for preventingapplication of heat to the stored liquids in the tank Illa. The conduit2|, within the chamber I6, instead of being bent upon itself, extendsupwardly to the upper portion of the chamber and a concentric or tubesleeve 55 surrounds said conduit and extends downwardly therearound tothe lower portion of the vaporizing chamber I6, as clearly shown inFigure 4. The upper end of said tube is secured to the upper end of thechamber with afiuid tight connection, whereby vaporized gas deliveredinto the chamber through the conduit 2| travels upwardly to the upperend of the conduit and into the tube, whereupon it is directeddownwardly to the lower portion of the chamber I6, spaced from the fluidoutlet 23.

Other principal parts of the device are generally the same as thosepreviously described and bear the same numerals. i I

If desired, the entire control assembly just .described maybe compactlyassembledin ashort cylindrical tank section Hla, as illustrated inFigure 4, to provide a compact prefabricated control unit which may beassembled at a factory and shipped to other points for assembly with thebalance of a storage tank which will be made at such point. In thismanner, the essential control mechanism is constructed and assembled atthe factory, where it may be accurately and correctly made to assureproper functioning.

A back-up ring 56 is provided at the open end of the short cylindricaltank portion Illa of the prefabricated unit and may be utilized foratta'ching the balance of the cylindrical storage tank thereto, bywelding in the usual manner.

The functioning of this modified form of the invention is exactly thesame as that of the form previously described. A liquid column willstand within the sleeve in'the annular space between said sleeve and thelower extended portion 50 of the chamber IE, as well as within the lowerportion of said chamber. Thus, a liquid column separating the vaporspace within the storage tank from the vapor chamber 15 is provided.

If desired, the fuel for supplying the heat applied to the vaporizingsection 22 may be derived from the service outlet line, as shown inFigure 4. A T 51 is connected in the service line, and a gas line 58,having a valve 55 and a burner 60 thereon, is connected to one branch ofthe T. The other branches are connected to the service line.

It will be seen, therefore, that a control system for liquefied gasstorage and dispensing device has been provided, which will in no casepermit liquid to. enter the service line, but will continue to delivergas vaporized by the heat absorbed by the main tank of the plant or bythe vaporizing section 22. Under conditions of heavy withdrawal,withdrawal over and above the capacity of the vaporizer, gas may bedelivered to the service outlet from the vapor space I? of the tank It).

It'will further be seen that a control system has been provided whereinthere are no mechanical seating valve portions or mechanisms. The entirecontrol of the flow of vaporized gas is by means of liquid columns.Further, since the heavy or rich gas which may condense in the chamberI6 is delivered to one arm of the gas conductor IS, the liquid column insuchconductor is maintained in adequate volume to control the flow ofgas from the vapor space of tank It to the chamber it.

Also, it will be seen that the device provides for reoffering of theheavy or rich gas in vaporized state to the. service outlet untiltemperature conditions are suitable for acceptance of the gas into theservice outlet.

Furthermore, since means has been provided for admitting vaporized gasfrom the vapor space of the storage tank to the vapor chamber I6,liquefied gas will not be delivered to the service outlet.

Also, it will be seen that a system has been provided which isparticularly adapted to'be assembled as a prefabricated compactcomponent of a complete system at a central point of manila facture, andwhich may be readily transported to other points for attachment ofsuitable storage vessels thereto.

It will also readily be seen that the system is particularly adapted foroperation above ground. and offers a practical system for the useoi'flame or other applied heat to cause vaporization'but may also beused for under-ground installations.

Furthermore, it is manifest that the system is simple in structure andoperation and is especially suitable for complete enclosure ,foroperation without fear of mechanical failure or high maintenance cost.

It will particularlybe noted that the baffle chamber 29 provides meansfor containing the heavy or rich mixture in the conduit 2|, in the eventof fluctuating demand or withdrawal which may cause liquid in theconduit to be forced toward the tank In as the volume of gas in theconduit 2& is increased, thus reducing the possibility of admixture ofsuch heavier mixture with the contents of-the tank.

The foregoing description of the invention is explanatory only, andchanges in the details of the construction illustrated may be made bythose skilled in the art within the scope of the appended claims,without departing from the spirit or the invention.

What I claim and desire to secure by Letters Patent is:

l. A liquefied gas storage and dispensing system including. a storagetank for holding liquefied gas under pressure, a conduit communicatingwith the lower portion of the tank for withdrawing liquefiedgas'therefrom and delivering said liquefied gas to a vaporizing section,a service outlet for vaporized gas from said vaporizing section, aconductor having one and communicating with the upper portion of thestorage tank and the vaporized gas therein and having its other endcommunicating with the outlet from the vaporizing section, and means forutilizing a colmen of liquefied gas in said conductor for normallyclosing off the flow cf vaporized gas through said conductor and forpermitting flow of such vaporized gas to the outlet when the level ofliquefied gas in the conduit rises to a predetermined level in thevaporizing section, the conduit communicating with the lower portion ofthe storage tank being provided with means limiting return of liquefiedgas from the conduit to the storage tank and a chamber for containingthe liquefied gas in the conduit in the event such gas in forced towardthe tank by fluctuations in withdrawals from the system, wherebyadmixture of liquefied gas in the conduit with the contents of the tankis reduced.

2. A compact control system for use with a liquefied gas storage anddispensing system including, a tank end section adapted to be connectedwith a storage tank for holding liquefied gas under pressure, a conduitcommunicating with a the lower portion of' said tank end section. and

adapted to receive liquefied gas from such section and deliver suchliquefied gas to a vaporizing section, an outlet for vaporizedgas from.said vaporizing section, a conductor having one end communicating withthe upper portion of the tank end section and the vaporized gas thereinand having its other end communicating with the outlet from thevaporizing: section, and means for utilizing a column or liquefied gasfrom. the tankin. said'conductor for normally closing oh? the flow ofvaporized gas through said. conductor and for permitting flow of suchvaporized gas to the outlet when the level of liquefied gas in the"conduit rises to a predetermined level in the vaporizing section.

'3. A liquefied gas storage: and dispensing system including, a storagetank for holding liquefied gas under pressure, a conduit communicatingwith the lower portion of the tank for withdrawing liquefied gastherefrom and delivering said liquefied gas to a vaporizing section, anoutlet from said vaporizing section for vaporized gas, an uprightconductor having its upper end communicating with the upper portion ofthe storage tank and the vaporized gas therein, a second uprightconductor having its upper end communicating with the outlet from thevaporizing section,said upright conductors having their lower endscommunicating, said conductors providing means for utilizing a column ofliquefied gas therein for normally closing off the flow of vaporized gasfrom the vapor space of the storage tank to the outlet, and forpermitting fiow of such vaporized gas to the outlet when the level ofliquefied gas in the conduit rises to a predetermined level in thevaporizing section.

4. A liquefied gas storage and dispensing system including, a storagetank for holding liquefied gas under pressure, a conduit communicatingwith the lower portion of the tank for withdrawing liquefied gastherefrom and delivering said liquefied gas to a vaporizing section, aservice outlet from said vaporizing section for vaporized gas, aconductor having one end communicating with the upper portion of thestorage tank and the vaporized gas therein and having its other endcommunicating with the outlet from the vaporizing section, means forutilizing a column of liquid in said conductor for normally closing offthe flow of vaporized gas through said conductor and for permitting fiowof such vaporized gas to the outlet when the volume of liquefied gas inthe conduit increases to a predetermined amount in the vaporizingsection, and means for conducting excess liquid from the conductor tothe conduit at the lower portion of the tank.

5. In a liquefied gas storage and dispensing system having a storagetank for holding liquefied gas under pressure and having a conduit forreceiving liquefied gas from the storage tank and vaporizing such gasand delivering vaporized gas to a service outlet, the improvement whichincludes, a conductor communicating with the vapor space of the storagetank and service outlet, means for utilizing a column of liquid fornormally closing ofi fiow of vaporized gas through said conductor andfor permitting fiow of such vaporized gas to the service outlet when thelevel of liquefied gas in the conduit rises to a predetermined level,means for preventing delivery of condensed components of the gas fromthe conduit to the service outlet, and means for conducting suchcondensed gas to the conduit for revaporization and redelivery to theservice outlet.

6. In a liquefied gas storage and dispensing system having a, storagetank for holding liquefied gas under pressure and a conduit forreceiving liquefied gas from a storage tank and for vaporizing such gasand delivering vaporized gas to a service outlet, the improvement whichincludes, a conductor communicating with the vapor space of the storagetank and with the service outlet, means for utilizing a column of liquidfor normally closing ofi fiow of vaporized gas through said conductorfrom the vapor space of the storage tank to the service outlet and forpermitting fiow of such vaporized gas from the vapor space of thestorage tank to the service outlet when withdrawal of vaporized gas fromthe conduit exceeds its delivery a predetermined amount, and means forconducting condensed components of the gas from the service outlet tothe conductor for maintaining the column of liquid in the conduetor.

it In a liqu fied a t rag and isp nsi g we tem having a storage tank forholding liquefied gas under pressure and having a conduit for receivingliquefied gas from the storage tank and vaporizing such gas anddelivering vaporized gas to a service outlet, the improvement whichincludes, a conductor communicating with the'vapor space of the storagetank and with the service outlet, means for utilizing a column of liquidin said conductor for normally closing off flow of vaporized gas throughsaid conductor and for permitting flow of such vaporized gas to theservice outlet when the level of liquefied gas in the conduit rises to apredetermined level, means for preventing delivery of condensedcomponents of the gas from the conduit to the service outlet, and meansfor delivering such condensed components to the conductor formaintaining the liquid column therein.

8. A liquefied gas storage and dispensing system including, a storagetank for holding liquefied gas under pressure, a conduit communicatingwith the lower portion of the tank for Withdrawing liquefied gastherefrom and delivering said liquefied gas to a vaporizing section, aservice outlet from said vaporizing section for vaporized gas,

a conductor having one end communicating with v the upper portion of thestorage tank and the vaporized gas therein and having its other endcommunicating with the outlet from the vaporizing section, means forutilizing a column of liquid in said conductor for normally closing offthe fiow of vaporized gas through said conductor and for permitting flowof such vaporized gas to the outlet when the volume of such liquefiedgas in the conduit increases to a predetermined amount in the vaporizingsection, and means for conducting condensed components of the gas fromthe service outlet to the conductor for maintaining the column of liquidin the conductor.

9. A liquefied gas storage and dispensing system including, a storagetank for holding liquefied gas under pressure, a conduit communicatingwith the lower portion of the tank for withdrawing liquefied gastherefrom and delivering said liquefied gas to a vaporizing section, aservice outlet from said vaporizing section for vaporized gas, aconductor having one end communicating with the upper portion of thestorage tank and the vaporized gas therein and having its other endcommunicating with the outlet from the vaporizing section, means forutilizing a column of liquid in said conductor for normally closing offthe flow of vaporized gas through said conductor and for permitting fiowof such vaporized gas to the outlet when the volume of such liquefiedgas in the conduit increases to a predetermined amount in the vaporizingsection, means for maintaining the column of liquefied gas in theconductor, and means for conducting excess liquids from the conductor tothe conduit at the lower portion of the tank.

. T. I-LDUFF.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,945,550 Hermsdorf Feb. 6, 19342,072,? 13 F-olmsbee et a1. Mar. 2, 1937 2,190,366 Mead Feb. 13, 19402,339,134 Baker et a1 Jan. 11, 1944 2,371,231 Duff Mar. 13, 1945

